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Abstract:

There is provided herein a robot-based electrical system for locating
holidays within coated pipe that does not utilize a grounding wire. In a
preferred arrangement, the robot will carry a metal rotating
brush/capacitive pad combination and changes in the capacitance in the
brush/pad circuit will be used to identify imperfections in the interior
coating of the pipe and especially those located proximate a girth weld.
In another preferred embodiment, a circumferential brush will be used
that allows testing of the integrity of the internal coating throughout
the length of the pipe as the robot travels the pipeline.

Claims:

1. An inspection robot for inspecting an interior coating of a pipeline
for the presence of imperfections proximate to a weld seam of said
pipeline, comprising: (a) a conductive brush positionable to be placed
into contact with said interior coating of the pipeline, said brush being
rotatable through an arc of substantially 360.degree.; (b) a capacitive
pad being positionable to be in contact with said interior coating of the
pipeline; (c) a power source in electrical communication with said
conductive brush and said capacitive pad, said power source at least
being adapted for creating a pulsed current between said conductive brush
and said capacitive pad; and, (d) a pulse detector in electronic
communication with said power source and said capacitive pad, said pulse
detector at least being adapted for detecting said pulsed current from
said power source through said conductive brush and said capacitive pad.

2. The inspection robot according to claim 1, wherein said conductive
brush is selected from a group consisting of a brass brush and a copper
brush.

3. The inspection robot according to claim 1, wherein said pulse detector
comprises a microprocessor in electronic communication with said
capacitive pad and with said conductive brush.

4. The inspection robot according to claim 1, wherein said capacitive pad
is selected from a group consisting of a conductive copper brush and a
conductive shoe.

5. The inspection robot according to claim 1, wherein said capacitive pad
is stationary.

6. A line travel inspection robot for inspecting an interior coating of a
pipeline for the presence of imperfections, comprising: (a) a
circumferential conductive brush positionable to be placed into contact
with the interior coating of the pipeline, said conductive brush being
oriented transversely to a longitudinal center axis of said pipeline and
extending through an arc of substantially 360.degree., thereby
simultaneously contacting substantially all of an inner circumference of
the pipeline; (b) a capacitive pad, said pad being positionable to be in
contact with the interior coating of the pipeline; (c) a high voltage
power source in electrical communication with said conductive brush, said
power source at least being adapted for creating a pulsed current between
said conductive brush and said capacitive pad; and, (d) a pulse detector
in electronic communication with said power source and said capacitive
pad, said pulse detector at least being adapted for detecting a pulsed
current from said power source through said conductive brush and said
capacitive pad.

7. The line travel inspection robot according to claim 6, wherein said
circumferential conductive brush is selected from a group consisting of a
brass brush and a copper brush.

8. The line travel inspection robot according to claim 6, wherein said
pulse detector comprises a microprocessor in electronic communication
with said capacitive pad and with said conductive brush.

9. The line travel inspection robot according to claim 6, wherein said
circumferential brush is segmented into at least four segments, each of
said segments being movable away from and toward said pipeline centerline
in order to place said each of said moved segments into contact with said
inner circumference of the pipeline.

10. The line travel inspection robot according to claim 6, wherein said
capacitive pad is selected from a group consisting of a conductive copper
brush and a conductive shoe.

11. An inspection robot for inspecting an interior coating of a pipeline
for the presence of imperfections, comprising: (a) a robot body; (b) a
conductive brush supported by said robot body and positionable to be
placed into contact with the interior coating of the pipeline, said brush
being operable to examine an inner circumference of said pipeline; (c) a
capacitive pad, supported by said robot body, said pad being positionable
to be placed in contact with the interior coating of the pipeline; (d) a
high voltage power source in electrical communication with said
conductive brush and said capacitive pad, said power source at least
being adapted for creating a pulsed current between said conductive brush
and said capacitive pad; and, (e) a pulse detector in electronic
communication with said power source and said capacitive pad, said pulse
detector at least being adapted for determining an amplitude of a pulsed
current from said power source through said conductive brush and said
capacitive pad.

12. The inspection robot of claim 11, wherein said conductive brush is
rotatable through an arc of substantially 360.degree..

13. The inspection robot of claim 11, wherein said conductive brush is a
circumferential conductive brush positionable to be placed into contact
with the interior coating of the pipeline, said conductive brush being
oriented transversely to a longitudinal center axis of said pipeline and
conformable to extend through an arc of substantially 360.degree.,
thereby simultaneously contacting substantially all of an inner
circumference of the pipeline.

14. An inspection robot according to claim 11, wherein said conductive
brush is selected from a group consisting of a brass brush and a copper
brush.

15. An inspection robot according to claim 11, wherein said pulse
detector comprises a microprocessor in electronic communication with said
capacitive pad and with said conductive brush.

16. The inspection robot according to claim 11, wherein said capacitive
pad is selected from a group consisting of a conductive copper brush and
a conductive shoe.

17. A line travel inspection robot for inspecting an interior coating of
a metal pipeline for the presence of imperfections, comprising: (a) a
robot body; (b) a circumferential conductive brush supported by said
robot body and positionable to be placed into contact with the interior
coating of the pipeline, said conductive brush being oriented
transversely to a longitudinal center axis of said pipeline when so
positioned and extending through an arc of substantially 360.degree.,
thereby simultaneously contacting substantially all of an inner
circumference of the pipeline; (c) a grounding wire positionable to be in
electrical communication with an uncoated portion of the pipeline; (d) a
high voltage power source in electrical communication with said
conductive brush and with said grounding wire; and, (e) a conductivity
detector in electronic communication with said power source, said
grounding wire and said conductive brush, said conductivity detector
being adapted for detecting a current from said power source through said
grounding wire and said conductive brush.

18. The line travel inspection robot according to claim 17, wherein said
conductive brush is comprised of a plurality of metal strands.

19. The line travel inspection robot according to claim 18, wherein said
metal strands are selected from a group consisting of copper strands,
brass strands, and aluminum strands.

20. The line travel inspection robot according to claim 17, wherein said
circumferential brush is segmented into at least four segments, each of
said segments being movable away from and toward said pipeline centerline
in order to place said segment into contact with said inner circumference
of the pipeline.

Description:

FIELD OF THE INVENTION

[0001] The present invention relates generally to the field of the
inspection of pipe and, more particularly, to the field of robotic
inspection of internal coatings in large diameter pipe such as that used
in pipelines to transport crude oil and other fluids.

BACKGROUND OF THE INVENTION

[0002] Large diameter pipe such as that used to transmit substances such
as oil and gas is manufactured in sections that are a few tens of feet in
length. Pipe diameters can vary considerably but typically are between
about 5 and 72 inches in diameter, although diameters outside of that
range are known. Pipelines are constructed from individual metallic pipes
(sections) which are laid individually end to end and then joined to one
another by means of a welded connection. Pipelines can extend for many
miles in length and are expected to last for years. Additional
information related to the general environment of the instant invention
can be found in, for example, U.S. Pat. No. 7,077,020, the disclosure of
which is incorporated herein but referenced as if fully set out at this
point.

[0003] The pipe of greatest interest herein is made of steel, thus it is
customary to apply some sort of coating to the interior surface of each
section of pipe to help protect it against corrosion by the fluids that
flow through it. Typically this coating is applied to the interior of the
pipe at the factory before the pipe leaves for installation.
Imperfections in the coating can, of course, lead to subsequent corrosion
and, ultimately, failure in the field. These imperfections might be due
to problems at the factory, subsequent handling, installation, etc. Thus,
it is common and desirable to determine the status of the coating as a
final step after its installation.

[0004] The point of contact between adjacent pipe sections is also a
potential source of failure in the field. In a typical arrangement, pipe
sections are placed end to end and welded together to form a continuous
pipeline. The welding at the joints (e.g., a "girth weld" or "field
joint") is also subject to imperfections of different sorts that might
have been created during the welding process. Further, the area near the
end of each pipe section (e.g., "coating cutback") is typically not
coated at the factory since such coating would be destroyed or corrupted
by the welding process. Thus, there will be a gap in the coating of two
pipe sections at their junction and it is desirable to coat at least that
portion of the inside of each pipe after welding and before beginning to
move fluids (to include gasses) through the pipeline. That operation must
obviously be performed from inside the pipe and robotic solutions to
perform this task are well known.

[0005] In the field multiple pipe sections are welded together to form a
continuous pipeline that may extend for many miles. In some cases, the
pipeline might be buried or submerged (e.g., placed on the ocean floor)
where it may be difficult to access subsequently. Thus, it is imperative
that the coating that is applied be unbroken or otherwise the useful life
of the pipe section could be radically shortened. Of course, failure of a
pipe section could result in release of its contents into the environment
and/or could necessitate a costly repair or replacement of that section.

[0006] Imperfections in the coating of a steel pipe are typically sensed
by way of a high voltage conductivity measurement. In a conventional
arrangement, a robot is sent through the pipe section trailing behind it
a wire that is placed in electronic communication with an uncoated
section of the pipe. The robot then applies an electric voltage to a
conductor (e.g., a brush with copper or brass strands) that is in contact
with the inner surface of the pipe. Since the coating is generally
nonconductive, pinholes, discontinuities, and other imperfections (i.e.,
"holidays") will allow a circuit to be completed which results in a
lowered resistivity, thus making such imperfections sensible via
conductivity measurements. Additionally, such an imperfection will
typically also manifest itself as a spark between conductive brush and
the pipeline wall, thereby providing a further indication of a holiday.
Holidays may be marked after they are detected (e.g., by applying a small
amount of highly visible paint or dye proximate to the pipe in the
vicinity of the holiday) after which insertion of a second robot unit may
be necessary in order to apply an additional coating to correct the
problem area(s).

[0007] As is indicated above, it is conventional for such robots to drag
behind them a long grounding wire which is attached to (or in electronic
communication therewith) the bare steel of the pipe. This connection
might be made by attaching the end of the wire opposite the robot to the
bare steel of the pipe which is usually found on its exterior or on the
inside of the pipe proximate to the point where the robot enters the
pipeline (e.g., the outermost coating cutback end). Of course, this wire
is subject to tangling or breaking and, if such happens, prior art robots
must be withdrawn from the pipeline and the grounding wire repaired. Such
removal and repair can take a considerable amount of time and, as might
be suspected, a delay in completion of this stage of the pipeline
construction will result in money lost to the operator.

[0008] Finally, a conventional approach to searching for holidays
proximate a girth weld involves the use of a robot that has a conducting
brush affixed to a rotating arm. As might be expected, in practice a
charge is applied to the brush as it is swept through a 360° (more
or less) arc. However, such an arrangement is not suitable for testing
the entirety of the interior of the pipe. Further, a rotating arm is
subject to a number of potential mechanical problems and, if such occurs,
the robot will need to be withdrawn from the pipe and repaired. Such
delays, of course, only increase the cost of the pipeline for the
operator.

[0009] Thus, what is needed is an apparatus for locating holidays in
coated pipe proximate a girth weld that does not suffer from the
disadvantages of the prior art. It would be preferred that such a system
would not utilize a grounding wire. Additionally, a new method of
detecting holidays throughout the length of the pipe is needed that does
not employ a rotating arm.

[0010] Heretofore, as is well known in the pipeline coating inspection
arts, there has been a need for an invention that was not subject to the
problems evident in the prior art. Accordingly, it should now be
recognized, as was recognized by the present inventors, that there
exists, and has existed for some time, a very real need for a system that
would address and solve the above-described problems.

[0011] Before proceeding to a description of the present invention,
however, it should be noted and remembered that the description of the
invention which follows, together with the accompanying drawings, should
not be construed as limiting the invention to the examples (or preferred
embodiments) shown and described. This is so because those skilled in the
art to which the invention pertains will be able to devise other forms of
the invention within the ambit of the appended claims.

SUMMARY OF THE INVENTION

[0012] There is provided herein a robot-based electrical system for
locating holidays within coated pipe that does not utilize a grounding
wire. In a preferred arrangement, the robot will carry a metal
brush/capacitive pad combination. Preferably, the brush and pad will be
extended to contact the interior coated surface of the pipe, and the
brush will sweep the coated girth weld. After a high voltage (preferably
DC) is applied to the brush /pad pair, a capacitor will be formed with
the internal coating acting as the dielectric. If a holiday is not
present, there will be no (or little) current observed. When the brush
encounters a holiday, the capacitance formed will be momentarily shorted,
and a high voltage will be rapidly presented on the pipe. The resulting
current will preferably be detected via a microprocessor or other
programmable logic device using circuitry connected to the capacitive
pad. Additionally, in some preferred embodiments a video camera will be
positioned on the robot so as to make it possible for a remotely situated
operator to observe a corresponding spark if such is created. Preferably,
the operator will have access to wirelessly transmitted real-time video
of the robot's operations as well as some sort of real-time indication of
the status of the brush.

[0013] According to another preferred variation, there is provided a
wireless grounding system for locating holidays within coated pipe
substantially similar to that described above, but wherein the brush
preferably takes the form of a circumferential (i.e., non-rotating) brass
brush that is positioned transverse to the center axis of the robot and
is designed to be placed into contact with the inner circumference of the
pipeline simultaneously. During inspection, the brush will preferably be
designed to maintain constant contact with the interior of the pipe while
the instant invention is moved therethrough. In this manner the entirety
of the internal coating of the pipeline may be rapidly inspected.

[0014] In still another preferred arrangement, there is provided an
apparatus for detecting holidays within coated pipe which utilizes the
circumferential (preferably) brass brush of the previously embodiment,
but which further utilizes a conventional grounding wire.

[0015] The foregoing has outlined in broad terms the more important
features of the invention disclosed herein so that the detailed
description that follows may be more clearly understood, and so that the
contribution of the instant inventors to the art may be better
appreciated. The instant invention is not limited in its application to
the details of the construction and to the arrangements of the components
set forth in the following description or illustrated in the drawings.
Rather the invention is capable of other embodiments and of being
practiced and carried out in various other ways not specifically
enumerated herein.

[0016] Additionally, the disclosure that follows is intended to apply to
all alternatives, modifications and equivalents as may be included within
the spirit and the scope of the invention as defined by the appended
claims. Further, it should be understood that the phraseology and
terminology employed herein are for the purpose of description and should
not be regarded as limiting, unless the specification specifically so
limits the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other objects and advantages of the invention will become apparent
upon reading the following detailed description and upon reference to the
drawings in which:

[0023] FIG. 6 contains an illustration of the embodiment of FIG. 4 in a
wire-grounded version.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Referring now to the drawings, wherein the reference numerals
indicate the same parts throughout the several views, there is provided
an apparatus for locating flaws such as holidays in the coating of the
interior of a pipe. According to a first preferred embodiment, there is
provided an inspection robot that has an electrical system for locating
holidays within coated pipe that does not utilize a grounding wire.

[0025] Turning first to FIG. 1, this figure illustrates a prior art
robotic device 10 suitable for searching for holidays that occur in
conjunction with pipeline internally coated girth welds. As is typical
with such devices, it utilizes a brush 30 that is affixed to a rotatable
arm 40. Additionally, a grounding wire is connected to the device 10 at
point indicated on drawing and is terminated remotely against an
uninsulated (e.g., uncoated) portion of the steel pipe. In operation, the
device 10 is pulled or pushed into position. If the brush 30 is not
already in contact with the interior of the pipe, the arm 40 will be
extended until it is. An electrical voltage will be applied to the brush
30 and, at about the same time, the arm 40 will begin to rotate.
Simultaneously, an internal electrical circuit will begin to monitor the
voltage on the ground wire. This circuit typically utilizes a
CPU/microprocessor of some sort which is preferably positioned onboard
the device 10, although it could certainly be situated elsewhere in the
train or any other location in electrical communication with the train's
circuitry. Additionally, in some instances an optional video camera will
transmit video of the rotating brush to an operator who is situated
remotely from the device. If the brush encounters a holiday during its
sweep, a drop in the impedance of the electrical circuit will be detected
and the presence of a holiday will be communicated to the operator.
Additionally, the holiday may be confirmable via the video link where
encountering a holiday results in a visible spark between the brush 30
and the wall of the pipe.

[0026] Turning now to FIGS. 2 and 3 which contain illustrations of a first
preferred embodiment of the instant invention, in a preferred arrangement
the instant invention will take the general form of a robot 200 that is
moved within a pipe. The instant apparatus 200 could be configured to
move under its own power within the interior of the pipe (e.g., an
electrical motor to drive it through the pipe might be situated onboard)
but in the preferred arrangement it will be towed or pushed by a separate
engine or crawler (not shown). Preferably, the robot 200 and the engine
that moves it will both be electrically powered.

[0027] The instant invention 200 will preferably be made to be part of a
robot train that travels under its own power through a pipe, the train
preferably containing the robot 200 as well as a portable power source,
an engine for moving the train through the pipeline, various support
electronics (e.g., video cameras, communications lines, etc.), and so on.
Ultimate control of the robot 200 and the train will preferably be
provided by a remotely situated operator who is in wired or wireless
contact therewith. Connector 230 is provided to hitch the robot 200 to
the next/adjacent device of in the robot train. Additionally, it is
conventional to provide one or more on-board (or otherwise situated)
microprocessors or other programmable logic devices that are designed to
handle various general operations according to methods well known to
those of ordinary skill in the art. In a preferred arrangement, one
portion of the instant invention will be made rotatable (e.g., front
member 225 in FIG. 2). That being said, those of ordinary skill in the
art will recognize a rotating arm (e.g., as is shown in FIG. 1) might be
utilized instead.

[0028] Incorporated into the rotating member 225 will preferably be a
conductive brush 220 which is made of, for example, strands of brass wire
or other conductive material (e.g., copper, aluminum, etc.). The instant
brush 220 is designed to sweep across the interior surface of the pipe as
it is rotated about the center axis of the apparatus 200. Of course,
those of ordinary skill in the art will recognize that, although the
element 220 is described as a conductive brush, that is only a preferred
embodiment and other sorts of conductors might be used instead (e.g., a
conductive pad, shoe, etc.). In practice, a pneumatic cylinder (not
shown) will preferably be used to move the brush 220 into contact with
the interior surface of the pipe and to withdraw it from such contact
when the device needs to be relocated.

[0029] The preferred capacitive contact component, i.e., the capacitive
coupling pad 215 of the instant invention, is carried in a separate
nonrotating portion 210 of the device 200. As can be seen, the coupling
member/capacitive pad 215 is preferably a stationary copper brush or, in
some cases, a conductive shoe, etc., that is positioned to be in contact
with the inner surface of the pipe. That being said, the exact form that
the capacitive pad 215 takes is not important to the operation of the
instant invention (e.g., it could be another brush). It is only necessary
that it be in electrical communication with the interior of the pipe and
at least somewhat electrically conductive.

[0030] In a preferred mode of operation, the instant invention 200 will be
moved to the proximity of a girth weld or other section of the pipe that
is to be tested. The arm on which the brush 220 is mounted will
preferably be extended until it contacts the inner-coated surface of the
pipe and the pad 215 will similarly be moved into contact with the wall
of the pipe. Preferably a high voltage DC charge will be applied between
the metal brush 220 and the pad 215, with the brush 220 having the higher
potential. Then, the brush 220 will be rotated through at least
360° (e.g., the brush 220 may make multiple passes over the same
surface) while it is monitored for changes in its electrical properties
(described in greater detail below) that signal that a discontinuity or
other imperfection in the coating has been encountered. Obviously, by
utilizing the (assumed known) position of the device 200 within the pipe
(e.g., its distance from the opening where it was inserted) together with
the angle of the arm at the time the holiday was encountered it is
possible to identify at least approximately the location that needs to be
patched or otherwise repaired.

[0031] During the holiday sensing process, capacitances are formed between
220 and the pipe, and between 215 and the pipe, with the internal coating
acting as the dielectric. The magnitude of the capacitances varies
according to the contact area, and coating thickness and dielectric
properties. According to standard electrical theory, the current through
a capacitor is proportional to the rate change of voltage across it.
During typical conditions without holidays, there is no current since the
preferred voltage source is DC. When the brush 220 does encounter a
holiday, the capacitance formed by 220 is momentarily shorted, and the
high voltage is rapidly presented across the other capacitance formed by
215. The resulting current is detected with circuitry connected to the
capacitive pad 215.

[0032] FIG. 5 contains a schematic illustration of the main electrical
components of the instant invention. First, a DC high voltage source 510
is placed into electrical communication with the brush 220 which is, in
turn, placed into contact with the coating on the interior of the pipe (a
dielectric), the brush, internal pipe coating and steel substrate
together forming a first capacitor C1 515. Note that the power source 510
might be situated within the robot 200 although it could also be located
elsewhere in in the train. The capacitive pad 215 is placed in contact
with the pipe internal coating, thereby forming a second capacitor C2
525. Finally, a pulse detector 520 will be placed into electrical
communication with the voltage source 510 and with the capacitive pad,
with the pulse detector 520 preferably being locating within the robot
200 although it could readily be situated elsewhere according to
techniques well known to those of ordinary skill in the art. All that is
required is that the pulse detector be in direct or indirect electrical
communication with the power source 510 and the capacitive pad 525.

[0033] In operation, the voltage source 510 will preferably generate a
high voltage pulse of known amplitude. In the preferred arrangement, the
pulse detector 520 will compare the amplitude of the received pulse which
has passed through the two capacitors C1 and C2 with the known amplitude
of the voltage source 510. Obviously, the presence of a holiday will tend
to increase the amplitude of the received pulse by, e.g., removing or
reducing the effect of the C1 (brush and coating) capacitor. A deviation
in the observed amplitude of the pulse either as compared with a
theoretical value or as compared with other/adjacent readings where the
coating is intact will be used to identify holidays. Of course, those of
ordinary skill in the art will recognize that a comparison between the
amplitude of the transmitted and received pulse is just one way of
examining the electrical signal for evidence of a holiday. More
specifically, changes in other pulse characteristics such as frequency or
phase shift, bandwidth change, etc., could alternatively be utilized to
detect imperfections.

[0034] Preferably, the pulse detector 520 will utilize at least one
microprocessor that is programmed to compare the transmitted and received
pulses, detect signals consistent with the presence of a holiday and
initiate action accordingly. For example, upon detection of a holiday the
microprocessor might transmit a signal to the remote operator, initiate a
process for marking the location of the holiday, etc.

[0035] Turning next to another preferred embodiment of the instant
invention, there is provided a line travel inspection robot 400 that
utilizes the wireless grounding system described above in combination
with a four quadrant circumferential inspection brush, where "four
quadrant" is used to indicate that one or more brush segments 410 are
combined to cover all areas of the interior of a pipe. As a consequence,
the instant embodiment 400 is well suited to continuously test the entire
length of a pipe.

[0036] FIG. 4 contains a preferred embodiment of this variation 400.
Preferably, the robot 400 will utilize a circumferential brass brush 410
of the sort generally indicated in FIG. 4. As is indicated, the brush 410
will be mounted transversely to the robot center axis so that it can
sweep substantially the entire inner surface of the pipe as the robot 400
moves through the pipe. Note that in the preferred arrangement the brush
will be segmented into four pieces 410, thereby making it at least
somewhat adjustable to match the diameter of the pipe that is under
investigation by adjusting the amount of overlap between adjacent
segments. That is, in the preferred arrangement the brush segments 410
will be movable toward and away from the longitudinal center of the
device 400 thereby changing the radius of their contact area with the
pipe. In the example of FIG. 4, each brush segment 440 can be adjusted in
and out (i.e., away from and toward the pipe wall) by
retraction/extension of this segment 440 via pneumatic (or electrical,
etc.) extension elements 450/455. Preferably, the extension elements
450/455 will be extended and retracted via a slidable plunger or a
similar mechanism. Once the brush segments 410 are in position against
the inside wall of the pipe, the train will begin to move and the search
for holidays will commence. In connection with this embodiment, it should
be noted that when the term "transverse" is used herein to describe the
orientation of the brush(s) 410 of the instant device 400, that term
should be broadly construed to mean that the brush or brush segments 410
generally extend away from the center line of the robot 400 or pipe and
toward its inner surface. Thus, this term should not be construed to
require that the brush(s) 410 be oriented to be strictly perpendicular to
the centerline.

[0037] Of course, the number of pieces 410 into which the brush is
segmented is not critical to the operation of the instant invention and
the number of segments might vary from as few as "one" (i.e., not
segmented) to an arbitrarily large number. It is important, though, that
the segments taken together substantially cover a full inner
circumference of the interior of the pipe.

[0038] The instant invention will preferably utilize a capacitive pad 415
which will project through the housing 430 and will operate generally
according to the scheme discussed previously. Additionally, in some
preferred embodiments the invention 400 will be further equipped with a
rotating arm/brush combination 420 that would, for example, allow it to
examine girth welds as has been described previously in connection with
embodiment 200. As such it is possible for the instant invention to
perform both girth weld and full-length internal inspections with a
single entry into the pipe.

[0039] In operation, the instant invention would be towed through the pipe
by a crawler that contains an electric motor, with the instant embodiment
200 preferably being physically attached to the next element of the train
via coupling 230. Upon receipt of a signal from the operator, the instant
invention will apply a potential difference across the circumferential
brush 410 and the capacitive pad 415 (e.g., perhaps on the order of about
2,000 volts as dictated by the coating manufacturer) and both will be
placed in contact with the interior of the pipeline. As the device 400 is
moved forward, in the preferred embodiment cameras and electronic
circuitry will be used to monitor for the presence of holidays which will
manifest as a spark or change in the electrical status of the brushes 410
and pad 415. Upon noting such, the instant invention will preferably mark
that location (e.g., with a stripe of paint or some other agent) so that
subsequently the imperfection can be patched according to methods well
known to those of ordinary skill in the art.

[0040] Note that this embodiment is designed to continuously test
longitudinal portions of the pipe for holidays, as compared with the
previous embodiment (and, more generally, with the prior art) which must
advance, stop, and rotate the section 220.

[0041] Turning to still another preferred embodiment, although the
preferred embodiment of the instant invention 400 utilizes the wireless
grounding approach discussed supra, an alternative is provided for
finding holidays in a factory or otherwise coated pipe substantially as
described above but wherein a grounding wire is utilized. In more
particular and as is generally illustrated in FIG. 6, according to
another preferred embodiment, there is provided an inspection robot 600
which is equipped with a circumferential brush 630 and a grounding wire
610. As has been explained previously, the grounding wire 610 typically
travels from the robot 600 back to the entrance point of the pipeline
where it is terminated against the pipe or against some other grounded
conductive structure. Connectors 625 are part of the robot train
circuitry which communicates information through the various devices of
the robot train. In the preferred arrangement, these circuits are
designed to provide access to power, handle signal transmission to and
from the robot, and receive and send control information. This embodiment
functions in a manner similar to that of a conventional holiday testing
robot which utilizes a rotating brush in that a voltage is applied to the
brush and it is monitored electronically (and visually via video in some
cases) for sparks that would be indicative of breaks/imperfections (or
holidays) in the internal pipe coating. The difference, of course, is
that the instant embodiment is suitable for continuously testing large
sections of pipe whereas a conventional robotic device must move to
position, rotate the brush, test the coating, stop the brush rotation,
move to the next location, etc. Obviously, the conventional approach is
too time consuming to be of much use in larger sections of pipe.

[0042] As has been described previously, it is preferred that one or more
on-board or otherwise situated microprocessors or other programmable
devices be used to control the movement and other operations of the
robot, detect holidays, communicate with the remote operator, transmit
information to the operator (via video or other means), etc. When a
holiday is discovered, it is preferable that the interior of the pipe be
marked as has been described previously so that it can be subsequently
located again for patching.

Conclusions

[0043] It should be noted that when the term "microprocessor" is used
herein, that term should be broadly construed to include any sort of
programmable or active device including, without limitation,
microcontrollers, conventional microprocessors, gate arrays, programmable
logic devices, etc. Additionally, even though the term microprocessor has
been used in the singular here, that term should also be construed to
cover instances where multiple microprocessors or other logical devices
act in cooperation.

[0044] Thus, the present invention is well adapted to carry out the
objects and attain the ends and advantages mentioned above as well as
those inherent therein. While the inventive device has been described and
illustrated herein by reference to certain preferred embodiments in
relation to the drawings attached thereto, various changes and further
modifications, apart from those shown or suggested herein, may be made
therein by those of ordinary skill in the art, without departing from the
spirit of the inventive concept the scope of which is to be determined by
the following claims.

Patent applications by Dale G. Davis, Beggs, OK US

Patent applications by Darrell L. Davis, Broken Arrow, OK US

Patent applications by David Paulley, Milton Keynes GB

Patent applications by James A. Huggins, Watts, OK US

Patent applications by John D. Carter, Catoosa, OK US

Patent applications by John D. Lindemann, Broken Arrow, OK US

Patent applications by Keith R. Roberts, Manford, OK US

Patent applications by Michael E. O'Neill, Tulsa, OK US

Patent applications by Russell Langley, Adair, OK US

Patent applications by Steve D. Hayes, Tulsa, OK US

Patent applications in class Where a material or object forms part of the dielectric being measured

Patent applications in all subclasses Where a material or object forms part of the dielectric being measured